Today, when it comes to soul-body dualism, the view that comes to mind is the substance dualism that Descartes systematized. As the name suggests, this dualism implies that there are two different types of substances. Similarly, although Ibn Sīnā also adopted a kind of substance dualism by stating that the soul is a different type of substance than matter, his dualism differs from Descartes’ in important aspects. It can be said that the most important reason for this difference is that (...) both ideas belong to different traditions. While Ibn Sīnā’s dualism carries the traces of Aristotelian hylomorphism, Cartesian thought is built on the post-Newtonian understanding of the mechanical universe. This significant difference has deeply affected soul-body conception of both philosophers. The aim of this study is to reveal the fundamental differences between the dualistic understandings of these philosophers in the context of soul-body. Thus, it will become clearer where the Avicennian dualism stands in terms of contemporary philosophy of mind. In this context, the first question to be addressed here is whether, according to both philosophers, the immaterial part of man means the same thing. The answer to this question is negative. The functions that Ibn Sīnā and Descartes attribute to the immaterial substance are quite different from each other. According to Descartes, it can be said that the soul is actually identical with the mind. Because, he describes the soul as the substance whose essence is to think. Here, Descartes is not only referring to theoretical calculations by thinking. It also includes phenomenal consciousness, that is, conscious phenomena, which is also called qualia in contemporary philosophy of mind. Thus, according to the Cartesian tradition, the fundamental distinction between soul/mind (the immaterial substance) and body is phenomenal consciousness: A thing is a soul only if it can have phenomenal consciousness. Whereas, Ibn Sīnā does not see phenomenal consciousness, which is the most basic function that the present Cartesian dualist tradition attributes to the soul, as the basic function of the immaterial substance. In fact, he does not even see it as a function of the human nafs. In other words, according to him, the main function of the human nafs is not to feel/experience or to have phenomenal consciousness. Such functions can also be performed by animals that do not have an immaterial substance. According to Ibn Sīnā, the main functions of the human soul are theoretical or universal thinking and being self-conscious. One of the places where this distinction can be seen most clearly is their thoughts about animal souls. Both philosophers argue that animals do not have an immaterial substance in addition to their material bodies. However, while this means that animals are unconscious automatons for one philosopher (Descartes), it does not mean anything like that for the other. Because, according to Avicenna, an immaterial substance is not necessary to have consciousness or feeling. However, according to Descartes, for a being to be conscious or sentient requires it to have an immaterial substance. Since animals do not have such (substantial) souls, Descartes saw them as unconscious robots. Another point where the same difference can be observed is an argument put forward by Avicenna to prove this immaterial substance, which he addresses as the human soul. According to Avicenna’s argument, the existence of an immaterial substance is necessary for man’s access to universal knowledge, not for having consciousness. However, according to the argument used in the Cartesian tradition and known as the unity of consciousness argument, the existence of immaterial substance is necessary for the unity of consciousness (not knowledge). The aim of this study is to reveal the basic differences between the dualistic understandings of these philosophers in the context of soul and body. In order to reveal these differences, the following points will be discussed: The question of whether animals are conscious and Avicenna’s argument mentioned above. Because the differences in the handling of these two issues by both philosophers will guide us to reveal the fundamental differences in their dualistic understanding. In this study, it will be argued that the dualistic understanding of Avicenna and Descartes in the context of soul-body are radically different from each other, especially over these two issues. (shrink)